13C‐Kernresonanzspektroskopische Untersuchung der Komplexierung von synthetischen «Carrier»‐Molekeln mit Ca2+‐Ionen

The complex formation between CaCl2 and the ion carrier ligands 1 and 2 was investigated with 13C‐NMR. spectroscopy. In methanol as solvent, the ligands form complexes with both 1:2‐ and 1:1‐stoichiometry (Ca2+/ligand). In the latter case, apart from solvent molecules, the ligand's two amide carbonyl groups and two ether oxygenatoms probably take part in the coordination of the metal cation. In contrast, when using a non polar solvent (CDCl3), 2 forms only a complex with 1:2‐stoichiometry, whereas 1 may also form a 1:1‐complex in which the ester carbonylgroups participate in the coordination too.